The goal of this research program is to achieve a functional "map" of the effects of ethanol upon neuronal activity for selected systems of the cat's brain. The effects of intravenous infusion of ethanol upon the multiple unit activity of the brain are investigated in cats bearing electrodes chronically implanted in one or more of the following systems: auditory system, association cortex, pontomesencephalic reticular formation, bulbar reticular formation. During testing, animals are prepared under neuromuscular paralysis to insure stimulus constancy for white noise bursts presented to determine the effects of ethanol upon evoked, as well as background neural activity. Ethanol is administered in a 2 min. "pulse" (25 percent v/v) in doses which yield peak blood alcohol concentrations of 0.05-0.50 percent. Saline controls are also run. Pupillary activity is monitored by an infrared pupilometer to provide a behavioral index of the animal's state, and the effects thereon of ethanol. Neural data are processed by a laboratory computer. Prime data include the rate of unit firing during and preceding repeated white noise stimulation, peristimulus histograms provided by an incremental plotter of background and evoked activity throughout the course of baseline treatment (10 min.) during and after ethanol administration (60 min.). Particular data analyses are concerned with the degree and temporal sequence of ethanol effects.